Recently, a felt pen writing tool is used for depicting, for example, an illustration wherein colored coating liquid such as aqueous or oily ink is supplied in the trunk part of the writing tool and is blown against the tip as a writing part thereof by the action of high-pressure air to be forced to atomize thereat. In conventional ones, as shown in FIG. 7, the writing tool A was inserted through the protruding part provided at the base body B, while a blow-off port C discharging high-pressure air was formed a short distance from the writing part A1 at the pointed end of the writing tool A. As a result, aside from the inconvenience of holding the tool by hand, the blown-off air jetting from aside was liable from time to time to permit the coating liquid to flow backward from the writing part A1 into the trunk part E, while on the other hand the air always incident upon the one side face of the writing part A1 was restricted to one and the same spot used. This arrangement not only helped to damage the writing part A1 but also easily incurred the unsmoothness of the efflux of the coating liquid toward the writing part A1, being accompanied by the difficulty in atomizing and spraying with a constant and smooth pace.
Further, conventional tools were so constructed that the coating liquid contained in the interior of the writing tool A was sucked out by the negative pressure occurring by the flowing of the air being blown against the writing part A1, so that the quantity of discharge of the coating liquid is sometimes insufficient to write when it is relatively hard for the coating liquid to ooze, for example, the structure of the writing tool A or the nature of the coating liquid, and so on.
Still further, in conventional tools, the relative position of the writing part A1 to the blow-off port C was fixed immovably, so that it was impossible to change by choice the state of atomization or spraying of the coating liquid, accordingly being poor in convenience for use.
Yet further, in conventional ones, a high-speed and abundant air stream was created attributable to the surge air pressure at the early stage of operation when the operational piece D was pushed down, worked on the writing part, and permitted the tool to spout out a great deal of coating liquid. When viewed like this, the use of such a kind of tool was premised to some extent of the skill to handle. In conclusion, this tool was poor in workability.